Integrating control method and apparatus for achieving uniformity of average conditions



Aug. 18, 1936. R. w. BROWN 2,051,781

INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 15 Sheets-Sheet 1 INVENTOR ATTORN 5Y5 Aug. 18, 1936. R BROWN 2,051,781

INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 13 Sheets-Sheet 2 INVENTOR 82 1719 78 17 so I R0 W. Brown AITO RN EYS Aug. 18, 1936. R w BROWN 2,051,781 INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1954 13 Sheets-Sheet 3 Q Q I INVENTOR R0 W. Brown ATTO RN EYS Aug. 18, 1936. R. w. BROWN 2,051,781

INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 13 Sheets-Sheet 4 INVENTOR R03 W Brown ATTORNEY5 3 Aug. 18, 1936. R. W.-BROWN INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 19:54

I 13 Sheets- Sheefl 5 INVENTOR ATTO RN EY5 Aug. 18, 1936. w BRQwN 2,051,781

INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY 0F AVERAGE CONDITIONS Filed July 27, 1934 1:5 Sheets-Sheet 6 r 1 34- 130 7 K 21 x23 W396 INVENTOR Rog W. Brown ATTORNEYS Aug. 18, 1936. R. w. BROWN 2,051,781

INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 13 Sheets-Sheet '7 INVENTOR Rog W Brown ATTORNEYS 1:5 Sheets-Sheet 8 Aug. 1936- R. w. BROWN I INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 INVENTOR R05 W Brown ATTORNEYS Aug. 18, R. W. BROWN INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 13 Sheets-Sheet. 9

m v14 n2 I5 I88 189 IBY A 47 ATTORNEYS Aug. 18, 1936. R. w. BROWN 2,051,781

- INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 15 Sheets-Sheet 1o 0 W. Brown f BM ATTORNEYS Aug. 18, 1936. R. w. BROWN INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27 1934 1s Sheets-Sheet 1i INVENTOR R015 W. Brown ATTO RN EYS Aug. 18, 1936. R. w. BROWN 3 INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27, 1934 13 Sheets-Sheet 12 INVENTOR Roy W. Brown ATTORNEYS Aug. 1-8, 19.36., R. w. BROWN 2,051,731 I I INTEGRATING CONTROL METHOD AND APPARATUS FOR ACHIEVING UNIFORMITY OF AVERAGE CONDITIONS Filed July 27', 1934 13 Sheets-Sheet 15 f INVENTOR 256 R09 W. Brown ATTO RNEY$ Patented Aug. 18, 1936 UNHTED STATES PATENT OFFICE Roy W. Brown, Akron, Ohio, assignor to The Firestone Tire & Rubber Company,

Akron,

Ohio, a corporation of Ohio Application July 27, 1934, Serial No. 737,242

15 Claims.

This invention relates to integrating control methods and apparatus for the adjustment of any average condition in contradistinction to adjustment of an immediate transient condition. It relates more particularly to method and apparatus for controlling a condition by means of integrating a series of concurrent or successive transient conditions in order to obtain a uniform average condition. The condition operated upon may be one of temperature, volume, power, voltage, flow, width, thickness, or any other condition that is met with in the arts and sciences and which may require adjustment.

The invention may, for example, be employed in the adjustment of temperature of a heat treating furnace, thermo-couples or pyrometers being installed about a number of positions in the furnace, and the invention being employed to adjust the average temperature at all of these points by successively taking readings on each of the heat measuring instrumentalities, integrating all of the readings, and making any adjustment necessary to produce any desired alteration in the average temperature taken at all of the points of measurement. The invention may also be utilized in the adjustment of the thickness of material such as milled or calendered sheets of steel, rubber, paper, or other sheeted material by measuring the thickness at a number of successive points on the sheet and then making an adjustment of the mill or calender rolls to increase or diminish the average thickness of the sheet as obtained by integrating the readings taken at the successive points thereof.

The invention may further be used in achieving average uniformity of continuous strip material, and more especially for automatically producing continuous strips of extruded plastic ma?- terial of uniform weight for a unit of length, as for instance, in the production of a continuous rubber tread slab in the manufacture of tires, which slab subsequently is cut into individual tread slabs of determinate length for incorporation in a pneumatic tire casing. Since the weight of the slab is a function of its width, thickness and composition, it will be seen that substantial control of the size of the slab is efiected when its average Weight is controlled.

By adjusting the weight of the slab by a con trol means which is effected by the average weight of a number of integrated successive portions of the slab, the effect of local inequalities is eliminated and average uniformity is attained with a minimum number of adjustments of the slab producing means.

The chief objects of the invention are to produce uniform average conditions; and to provide an improved method and apparatus for accomplishing the aforesaid object. A further object is to provide apparatus that will return to a determinate point of starting after each adjustment phase of operation. Other objects will be manifest.

While the invention may be utilized in the adjustment of any average condition, apparatus for the production of a continuous tread slab of average uniformity will be illustrated herein as an illustrative embodiment of the invention.

The apparatus comprises the usual extruding machine for forming a continuous strip of material, a continuously driven conveyor for removing the said strip, and means for automatically correlating the linear speed of the conveyor with the speed of extrusion of the strip according as the strip is over or under a determinate unit weight, to produce such a tension or compression in the strip as will restore it to said determinate unit weight.

Of the accompanying drawings:-

Figure 1 is a plan view of apparatus embodying the invention, in its preferred form;

Figure 2 is a side elevation thereof viewed from line 2-4; 1 a

Figure 3 is a plan view, on a larger scale, of a portion of the apparatus shown in Figure 1, as viewed from the line 3-3 of Figure 2, the same consisting of mechanical means for adjusting a conveyor-speed-control mechanism;

Figure 4 is a section on the line 4-4 of Figure 3;

Figure 5 is a section on the line 5-5 of Figure 1;

Figure 6 is a side elevation of the mechanism shown in Figure 5, as viewed from the right thereof, parts being broken away and in section;

Figure '7 is asection on the line 1-1 of Fig ure 6;

Figure 8 is a section on ure 2 showing in plan, mechanism comprising a source of light, a light sensitive device, and means whereby variations in the weight of the work effect corresponding variations of the intervals that the light responsive device is exposed to the light source;

Figure 9 is a section on the line 99 of Figure 8;

the line 88 of Fig- Figure 10 is a section on the line I0l0 of Figure 12 is a plan view of an integrating device;

Figure 13 is a side elevation of the integrator, as viewed from the right of Figure 12;

Figure 14 is a front elevation of the integrator, as viewed from the near side of Figure 12;

Figure 15 is a section on the line l5--i5 of Figure 12;

Figure 16 is a section on the line Iii-16 of Fig ure 12 Figure 17 is a front elevation of a timer device;

Figures 18, 19, 20 and 21 and 22 are sections on the lines l8l8, |9-l9, 2829, 2|-2l and 22-22 respectively of Figure 17, and

Figure 23 is a wiring diagram of electrical elements of the apparatus.

Referring to the drawings, 25 is an extruding machine of known or preferred type driven by a motor 26, and 21 is a continuous strip of plastic, unvulcanized, rubber composition extruded therefrom. Adjacent the delivery head of the extruding machine 25 is a framework 28 carrying a conveyor that for convenience is made in two endless sections 29, 39, said sections being longitudinally spaced apart from each other so that a numbering device comprises a suitable die-roller 3! over which the strip 21 passes in moving from conveyor belt 29 to conveyor belt 39, and a cooperating presser roller 32 that rests upon the work and presses it against said die-roller 31. The conveyor belts 29, 30 move in the same direction at the same speed, and to this end the shafts 33, 34 of the adjacent supporting rollers of the respective conveyor belts are provided with respective sprockets that are connected by a sprocket chain 35, shown best in Figure 1. A sprocket chain 36, Figure 1, may be provided for driving the dieroller 3| from the driven shaft 33. At its delivery end the conveyor belt 39 is carried upon a supporting roller 31 mounted upon a shaft 38.

Below and beyond the conveyor belt 35 is a cooling system comprising three belt conveyors 40, 4| and 42 that travel at the same speed as belt 39, and receive the work from the latter and convey it back and forth while a cooling spray is directed upon it.

For driving the aforesaid conveyor belts in unison, the shaft 34 of conveyor belt 39 is provided with a sprocket that is connected by sprocket chain 44 with a sprocket 45 on shaft 46 of a reduction gear device 41, and a second sprocket on shaft 48 is connected by a sprocket chain 48 with a sprocket 49 on shaft 58 of supporting roller 5! of conveyor belt 48. Suitable means (not shown) is provided whereby the conveyor belts 4|, 42 are driven from the belt 40.

The reduction gear device 41 is driven by means of an oil motor 53 to which it is directly connected, and said oil motor is driven by an oil gear 54 to which it is connected by fluid conducting pipes 55, 56. The oil gear 54 is driven by an electrical motor 51, and is adjustable to control the speed of oil motor 53, and consequently the conveyor belts, either manually, or automatically by electrical devices. I

For manual adjustment of the oil gear 54, the control shaft 58 thereof (see Figure 3) is provided with a sprocket 59 connected by a sprocket chain 69 to a sprocket 6| on a shaft 62 that is journaled in suitable brackets mounted upon the framework 28. The opposite ends of shaft 62 are provided with respective hand-wheels 63, at opposite sides of the framework, by means of which the control shaft 58 may be turned through the connections described.

Automatic adjustment of control shaft 58 is effected by means of a reversible electric motor 65 that has built-in reduction gear mechanism including a driving pinion 56. The latter is adapted to mesh with a gear 68 fixed on a shaft 69 with a gear 19, said shaft 69 being journaled in a fixed bracket H. The gear 19 is meshed with a gear 12 on control shaft 58 of oil gear 54, the gears 68, 19 being of such relative sizes as to effect further reduction of speed between pinion 55 and gear 12. The motor 65 is mounted for axial movement whereby its pinion 66 may be in mesh or out of mesh with gear 98, the latter condition obtaining when the apparatus is arranged for manual adjustment of control shaft 58. To this end the motor 65 is mounted upon a base plate 14 that is slidably mounted upon a supporting structure 15. The latter is formed beneath base plate 14, with an elongate slot 16 through which projects a pair of spaced lugs 11, 11 extending downwardly from said base plate. Positioned between said lugs and engaging both of them is an eccentric 18 that is mounted upon a shaft 19 that is journaled in the structure 15, transversely thereof. A projecting end of shaft 19 is provided with an operating lever 89, and an adjustable clip 8! is mounted upon structure 15 for engaging and holding lever 89 in place when the motor 65 is so positioned that pinion 8'5 meshes with gear 68. A rest 82 is provided for lever 89 in its alternative position. Bolts 83, 83 may be provided for holding the base plate 14 securely in place in either position of the motor.

Means subsequently to be described is provided for driving the motor 65 in alternative directions that correspond to overweight or underweight conditions of the strip 21, and for varying intervals that have a direct relation to the extent of said overweight or underweight. Means also is provided for disconnecting the entire conveyorspeed-adjusting mechanism, including motor 65, whenever the apparatus is idle and the conveyors are not in motion, said means comprising a centrifugal switch mechanism generally designated 85 and shown in detail in Figures 5 to '7.

The centrifugal switch mechanism is enclosed in a box mounted upon framework 28 beside conveyor roller 31, and comprises a pinion 81 that extends from said box and meshes with a gear 88 mounted upon the shaft 38 of said roller 31. Interiorly of said box, the shaft of pinion 81 carries a bevel gear 89 meshed with a bevel gear 98 on the lower end of a vertical shaft 9|. The upper end of shaft 91 carries a rotor or plate 92 and eccentrically mounted upon the latter is a mercury switch 93, the arrangement being such that said switch is closed when the rotor is rotating and conveyor 30 moving and open when they are stationary.

Means also is provided for disconnecting the entire conveyor-speed-adjusting mechanism whenever the trailing end of strip 21 passes off the moving conveyor 39, and for automatically reconnecting said mechanism whenever the leading end of the succeeding strip passes the same point. To this end a rock shaft 95, Figure 6, is journaled in the wall of a switch box 96 that is mounted upon framework 28 just beyond roller 31. A similar rock shaft is journaled in a bracket 91 on the opposite side of the framework. The adjacent ends of said rock shafts carry respective radial arms 98, the free ends of which carry a rod 99 extending transversely of the framework, parallel to and adjacent roller 31. A rotatable sleeve I09 is mounted upon rod 99, the arrangement being such that the strip 21 is in engagement with sleeve I06 when passing from conveyor 30 to conveyor 49, the weight of the strip holding rod 99 and arms 98 in the positions shown in full lines in Figure 6. The arms 98 are provided with respective rearwardly extending counterweights IOI adapted to tilt them and rod 99 to the broken line position of Figure 6 when no strip is resting upon said rod. Within switch box 96, rock shaft 95 carries a bracket I02 upon which is mounted a mercury switch I03, the latter being closed when tilted to the full line position shown, during the normal operation of the apparatus, and open when there is no strip 2'! resting on rod 99.

Broadly, the linear speed of the conveyor belts 29, 30 is controlled by the direction of rotation and duration of time that motor 65 is running, which factors are controlled by the length of time that a pair of light-responsive devices are exposed a1- ternatively to a constant light source, and the time of exposure of the light sensitive devices is controlled by the magnitude of the overweight or underweight of the strip 21.

The overweight or underweight of the strip 21 is determined by a weighing scale I05 of known type that is suitably constructed to accomplish the purpose desired. To this end the scale is mounted upon the top of framework 28, over the conveyor belt 30, and is provided with a depending yoke I06 that carries a roller I01 upon which the upper reach of belt 30 rests. The scale has an upwardly extending swinging arm or indicator I08, Figure 11, that is exactly in vertical position when the work on belt 39 is exactly the weight desired, said arm swinging to one side or the other according as the weight of strip 27 varies from the desired normal. Vertically adjustable rollers I09, I89 are positioned beneath belt 30 on each side of roller IQ! for adjusting the weight of the material suspended from yoke I08 to balance the scale and bring the arm I08 thereof initially to normal position.

Positioned atop of scale I05 is a closed housing I l I having an elongate slot I I2 in its bottom, centrally thereof through which scale arm I08 extends. Near one end of the housing II I is a partition IIB of light and heat insulating material, and in the end-chamber of the housing defined thereby is a light-source consisting of an electric lamp I I4 of considerable brilliance, say 500 watts, This end of the housing may be provided with a multiplicity of vanes H5, H5 to conduct heat therefrom. The partition H3 is formed with a horizontal, rectangular slot H6, and mounted over said slot, cxteriorly of the lamp-chamber, is a pair of lenses consisting of a plano-convex lens Ill, and a plano-cylindrical lens II8 having its axis parallel to slot H6. The function of these lenses is to transform the light passing through slot IIB into a horizontal beam or band of light of uniform length and of constantly diminishing width, said beam conveying to a focal line F some distance from said lenses as is most clearly shown in Figures 8 and 9.

"tween the aforesaid lenses and the focal line e free end of indicator arm I08, which arm an nrcuate plate I20 that intersects the .m and cuts ofi all of it except that porti 1 which passes through a relatively narrow, vertical slot i2I, Figure 11, formed in said plate and arm. Between plate I20 and the focal line F is a stationary plate I22 formed with an elongate horizontal slot 523 of slightly less width than the light beam at this point. Thus it will be seen that only a small patch of light of great and uniform intensity falls upon the focal line F, and that its position longitudinally of said focal line is controlled by the overweight or underweight condition of the strip 21 as denoted by the position of the indicator arm I08.

A rotary shutter I25 has its axis coincident with the focal line F. Said shutter is a hollow, cylindrical structure with closed ends, and is journaled upon end bearings I26, I26, Figure 10, carried by respective spindles i2? adjustably mounted in a suitable bracket I28, which bracket also carries the filter plate I22. Gne end Wall of the shutter IE5 is provided with a gear I29 that is meshed with the driving pinion I 39 of a reduction gear device it! mounted upon one end of a motor I32. The latter drives the shutter at about 24 revolutions a minute. The shell or cylindrical wall of the shutter I25 is cut away at each end thereof, and at diametrically opposite points, to provide four apertures I34, I35 in the shell, which apertures are substantially of ogival shape, their apices being blunt and directed toward the middle of the shell, but spaced from the latter so that there is an imperforate circumferential region at the middle of the shell. The apertures I 34 permit the small beam of light from lamp I I4 periodically to reach the focal point F at the axis of the shutter whenever the strip 21 is over or under gauge and said beam of light is diverted by arm I98 to either side of the imperforate medial region of the shutter shell.

When the strip is exactly the proper weight, the light beam falls on the imperforate medial region of the shutter and thus is out off. Because of the rotation of shutter I25, the beam of light that reaches focal line F is periodically cut off, and because of the peculiar shape of apertures I 34, the intervals that the beam reaches said focal line will vary in duration according to the position of the beam longitudinally of said focal line and shutter, being of short duration when the beam falls near the middle of the shutter and longer when the beam falls adjacent the respective ends of the shutter. Because the apertures I34 at opposite ends of the shutter are symmetrical in shape and disposed diametrically opposite each other, such light as reaches the focal line F continues therebeyond and passes out the opposite side of the shutter. It will thus be seen that when the strip 2i is overweight the beam of light will pass through one end of the shutter and when the strip is underweight it will pass through the opposite end thereof and that the intervals that the beam passes through the shutter will vary in duration in direct proportion to the extent of said overweight or underweight condition.

At the side of the shutter I25 opposite the filter plate IE2 is a frame I38 formed with an elongate, horizontal slot IS'I, said frame supporting a pair of piano-convex lenses 33, ISBa. The latter are arranged side by in alignment with the apertures Et i in the opposite ends of the shutter shell. Said lenses are adapted to intercept the beam of light passing through the shutter I25 and slot I31 and to refract said beam toward respective light responsive devices. Lens I38 deflects the beam of light passing through the shutter when the strip beside the respective electric eyes I39, I39a in the housing IM, and operate in conjunction with them as subsequently will be explained.

Non-uniformity of weight of the strip 21 may be the result of lumps in the stock, or because of changes in the temperature and/or consistency of the stock. It is not desired to adjust the speed of the conveyor belt because of temporary or local conditions in the stock, and for this reason adjustment to the drive of motor 65 is made only about every thirty-five seconds, this time interval being controlled by a timer mechanism mounted in an instrument cabinet M2, Figure 1, which may be positioned adjacent the apparatus. The stock is gauged at the rate of twenty-four times a minute or once every two and one-half seconds by the light-responsive mechanism previously described, and the mean condition revealed by said gauging controls the duration and direction of drive of motor 65 at the adjusting period. The mean condition of the stock is obtained by integrating mechanism controlled by the light responsive devices, said integrating mechanism being mounted in instrument cabinet I52, and being illustrated in Figures 12 to 16 of the drawings.

The integrating mechanism comprises a disc motor of which I55, I65 are the respective top and bottom frame plates, M6, I46 are corner pillars connected thereto and holding them in spaced relation, and I41 is a depending bracket secured to top plate I64. J ournaled in the bracket I 13 is a rotor shaft I66 that has a rotor disc I 59 mounted centrally thereon, said shaft M8 extending upwardly through top plate Hi6 and having its upper end formed with a driving pinion I55.

The disc I26 is driven alternatively in opposite directions by opposed magnetic coils located at diametrically opposite points with relation to said disc. The coils at one side of the disc comprise a pair of series-connected field or current coils I55, I5I positioned above the disc I49 and supported by bracket I52 from top plate I65, and a potential coil I positioned below disc I49 and supported mainly by bracket MI.

The aforesaid coils drive the disc I 49 in counterclockwise direction as viewed in Figure 12 when the strip 21 is underweight. The disc I49 is driven in the opposite direction when the work is overweight by the coils on the opposite side of the disc, which coils consist of field coils I5Ia, I5Ia carried by bracket I52a, and a potential coil I530. carried by bracket MT. The pinion I56 on shaft I 56 is meshed with a gear I55 that is mounted upon a vertical shaft I56, Figure 12, that is journaled in a bearing box I5? on top plate I44. The shaft I56 also has fixed thereon a gear I58 that is meshed with a gear I56 fixed upon a vertical shaft I66 journaled in a bearing box I6I on top plate M 5, as is most clearly shown in Figure 15. Concentrically mounted upon the top face of gear I56 is an annular structure I62 of dielectric material, and mounted fiush upon the top face of said structure is an arcuate, metal contact plate I55 of somewhat less than 180 degrees in extent. The respective end portions of contact plate I63 consist of relatively short sections I64, I64 that are insulated from the main section. The plate I63 is electrically connected through connections subsequently to be described, and plate sections I64 are similarly connected through a resistance coil I65 supported upon gear I56 concentrically with structure I62.

A triangular plate IB'I of dielectric material is supported upon corner posts I68, I68 rising from top plate I44 of the integrator said plate I61 overlying gear I59 and structure I62. Secured to the underside of plate I61 are brackets I69, I66 upon which respective metal brushes I'IIJ, IlIla are pivotally mounted, said brushes extending in diametrically opposite directions and having their free ends in engagement with the top surface of dielectric structure I62 or contact plates I63, I54 according to the angular position of gear I59 which in turn is controlled by the disc motor.

Respective compression springs III I II I mounted in housin shells I'IZ, I'Izf on. plate I677 are provided for urging brushes I'Iil, I'IIla into contact with said contact plate. Electrical connection with contact plate I63 and resistance coil I65 is made through a metal bridge I'I3 that is mounted upon dielectric plate I61 and spanning the axis of shaft I66, an axial rod IM having a sliding fit in an aperture in said bridge extending downwardly therefrom into a metal cup I175 that is mounted upon the upper end of shaft I66 so as to rotate therewith, but being insulated therefrom. A bath of mercury H6 in cup I75 makes good electrical contact between rod I'M and cup I75, and a conductor II'I extends from said cup to resistance coil I65 and to contact plate I63. The arcuate extent of the contact plate I63 and plate sections I65 is such that it is impossible for both brushes no, IllEia to be in touch with them at the same time, and at one position of the integrator, called the neutral position and shown in Figure 12, both of said brushes are upon dielectric material I62. The arrangement is such that when the strip 2'! is underweight, the coils I5I, I53 are energized to drive the rotor disc I49 in counterclockwise direction, the coils I5Ia, I53a driving the disc in the opposite direction when the strip is overweight. The contact members I63, I64 rotate in the same direction as disc I 49 when the latter is driven, with the result that either brush I16 or I'IOa may be engaged thereby. The presence of the resistance coil I65 in the electrical connection of members I64 prevents arcing when the brushes engage the latter or move therefrom onto member I63. If the work remains in extreme underweight or overweight condition during the entire interval between adjusting operations, the disc I49 will be turned angularly a maximum of 160 degrees.

Concentrically mounted upon the perimeter of dielectric structure I62, in spaced relation thereto, is an annular cam structure I80, the upper marginal face of which is formed with a cam surface comprising relatively short regions I8I, I8I of intermediate height disposed at diametrically opposite points of the cam, an elevated region I82 extending from one region I8I to the other on one side of the cam, and a depressed region I83 of equal length on the opposite side of the cam. Engaging said cam surface is a cam roller I84 on the free end of a lever arm I85 that is attached to one end of a rock-shaft I86 that is journaled in a pair of spaced arms I87 of a bracket that is mounted upon top plate I44. Between said arms said rock-shaft I36 carries an angular rocker arm I68, and attached to opposite sides thereof by spring clips I89, I89 are two 3-pole mercury switches I96, I90. These switches are interconnected, as shown in Figure 23 so as to constitute, in effect, a single reversing switch controlling the direction of rotation of reversible motor 65, and

preventing it from being driven if the mean condition of the work is at proper gauge. The cam I is so disposed angularly with relation to dielectric member I62 that when the latter is in the neutral position shown in Figure 12, cam surface I BI is in engagement with cam roller I64 and mercury switches I99 are in the neutral position shown best in Figure 16, at which time the switches I99 are open, the motor 65 is idle, and the strip 21 is exactly the proper gauge. Under these conditions, rotation of cam I89 in either direction will tilt switches I99 one way or the other and thus permit the motor 65 to be driven in the proper direction to adjust the speed of conveyor belts 29, 39.

Since the length of time that the disc motor is driven in either direction is in direct proportion to the extent of the off-gauge condition of the strip 21, it will be seen that the angular position of cam I89, between speed adjusting operations, represents the mean condition of the work rather than its instantaneous condition.-

The timer mechanism hereinbefore mentioned is shown in Figures 17 to 22 inclusive. Said timer mechanism comprises a vertically arranged baseplate I92 and two spaced-apart brackets I93, I94 secured thereto, said brackets being connected to each other by a pair of tie-rods I95, I96. Said brackets also support a cam shaft I 91 and a rockshaft I98, which shafts are journaled at their respective end portions in said brackets. One end portion of cam shaft I97 extends beyond bracket I94 and has journaled thereon a gear I99 that is positioned between a pair of friction discs 299, 299, the latter being backed by metal discs 29I, 29I that are keyed to shaft I9I, the outermost disc 29! being movable axially of the shaft. A leaf spring 292 mounted between the outermost disc 29I and a nut 293 on the end of the cam shaft urges the friction discs 299 and gear :99 into frictional driving engagement. The arrangement is such that the cam shaft I9? rotates with gear i99, but the latter may slip on the shaft if the shaft should refuse to rotate because of jamming of the cams or for any other cause such as the application of braking means to the cam shaft. The gear I 99 is driven by a pinion 294 with which it is meshed, said gear 294 being a part Of reduction g, that is generally designated 295, associated with a motor 296 that is carried by a bracket support 297 secured to end bracket Keyed to cam shaft I94 of the timing device. I9! is a sleeve 298 having thereon three disc cams 299, 2I9 and 2H respectively, and a singletooth ratchet 2 I2, said cams and ratchet serving purposes presently to be described. During normal operation, the motor 296 is constantly driven.

Mounted upon base-plate I92, beside bracket I93, is a solenoid coil 2I4, the armature 2I5 of which is mounted for pivotal movement by being secured at its lower margin to a shaft 2I6 that is journaled in a pair of bearing brackets 2II, 2H on said base-plate. Mounted upon a projecting end portion of shaft 2i 6 is a lever arm 2 I8 that is connected by an adjustable link 2I9 to the free end of a rocker arm 229 mounted upon rock-shaft I98. Thus the latter is given determinate angular movement when the solenoid coil 2I4 is energized, and returned to a determinate inoperative position when said coil is ole-energized. The operation of coil 2 I4 is controlled by switches 93 and I93, which switches are connected in series, with the result that said coil is energized whenever conveyor belt 39 is being driven and a strip 27 is passing therefrom onto conveyor 49.

As hereinbefore stated, motor 65 is driven periodically about every 31 seconds, the motor being controlled by a pair of mercury switches 222, 223 across two of the wires in its circuit. As is best shown in Figures 17 and 21, switches 222, 223 are mounted upon a common support 224 that is pivotally mounted at one side upon tie-rod I95. The support 224 is formed with an arm 225 that has a cam roller 226 on its free end, which cam roller normally rests upon cam 2. Throughout the major portion of its periphery the cam 2 II supports member 224 in the full line position shown in Figure 21, in which position switches 222, 223 are open and motor 65 is idle. Less than one-fourth the periphery of cam 2 is formed with a depressed cam surface 2I In which permits support 224 to tilt to the broken line position shown in Figure 21 to close the said switches and start the motor. The cam 2 I I makes one complete revolution every thirty-five seconds, the length of surface 2I Ia being such that the motor 65 may be driven for a maximum of 5.6 seconds during each revolution of the cam.

A dog 22'! on rock-shaft I98 has its free end positioned beneath the free end of switch support 224 so as to lift the latter and open the switches thereon whenever solenoid coil 2 I 4 is deenergized. This will stop the drive of motor 65 if it is then being driven. Solenoid coil 2I4 also controls the drive of timer motor 296 through the agency of a mercury switch 229, which switch is mounted upon a support 239 that is pivotally mounted at one side upon tie-rod I95 (see Figure 19) The free end of support 239 is engageable by a dog 234 mounted upon rock-shaft I98.

The arrangement is such that the switch 229 is in the broken line position of Figure 19 and closed when the coil 2I4 is energized, thus delivering current to motor 296. When coil 2I4 is de-energized, dog 23I opens switch 229.

It is desirable that the timing device always start and stop at the same angular position of its cams, and to this end a mercury switch 233 is provided in the circuit of motor 296. Switch 233 is mounted upon a. support 234 that is pivotally mounted at one side upon tie-rod I95. A lever arm 235 is formed on support 234 that has its free end provided with a cam roller 236 that rests upon the periphery of cam 299. The latter normally holds the switch 233 in the broken line position shown in Figure 18, in which position the switch is closed so that power may be delivered therethrough to motor 296. There is a short notch or depression 299a in cam 299, said depression acting to tilt switch 233 to the full line position shown to open it. If will be observed with reference to Figure 23 that the opening of switch 233 will not stop motor 296 unless switch 229 also is open, the arrangement being such that no matter when switch 229 is opened by solenoid 2| 4, motor 296 continues to run until stopped by cam 299 opening switch 233.

This construction assures that the cams always start and stop at the same angular position. One important result of this arrangement will be apparent from reference to Figure 21 in which it will be seen that when the apparatus is started after being stopped, cam 2II makes more than three-fourths of a revolution before closing switches 222, 223 to start motor 65. This allows a substantial amount of work 21 initially to pass over conveyors 39, 49 and several gauging operations to be made before any adjustment of the speed of said conveyors is made.

To prevent over-run of motor 296, when switches 229, 223 are opened, from carrying cams 299, 2I9 and 2 past stopping position, rockshaft I99 has pivotally mounted thereon a depending pawl 238, the free end of which is movable into the orbit of the single tooth of ratchet 2I2. A forked bracket 239 is fixedly mounted upon rock-shaft I 98"astraddle' pawl 238, the forks thereof being connected by spaced pins 246, 240 disposed before and behind pawl 238. Thus when the solenoid coil 2114 is energized or deenergized, the pins 246 swing the pawl 238 out of or into the orbit of the single tooth of ratchet M2. The cam shaft I91 is positively stopped when said ratchet engages the pawl, notwithstanding over-run of motor 266 which merely causes slippage between gear I99 and friction discs 269. The construction is such that there is lost motion between rook-shaft I98 and pawl 238 whereby exactness of adjustment between solenoid 2E4 and the pawl is obviated, and when the solenoid is energized, the armature H5 attains momentum before it is required to withdraw the pawl from. the ratchet 2 I2 so that less power is required to overcome the friction therebetween.

When the solenoid 2I4 is de-energized for any of the reasons mentioned, it is desirable to discontinue stock-gauging operations and to this end a mercury swltch 242 is included in the circuit that comprises lamp H4 and motor I32. The switch 242 is mounted upon a support 243 that is pivotally mounted at one end upon tie-rod I95, the free end of said support being engageable with a dog 244 on rook-shaft I98. The switch 242 is closed when in the broken line position shown in Figure 22, and open when tilted by dog 244 to the full line position shown therein, when thesolenoid H4 is tie-energized.

The timer mechanism also includes a switch that is in the integrator circuit and which allows the disc motor to be driven in either direction according to the underweight or overweight condition of the strip 21, during the intervals between belt-speed-adjusting operations, and which causes the motor disc and cam I86 to return to neutral position during the adjusting operation, the time required for the cam to reach said neutral position being the interval that motor 65 will be driven. Said switch, best shown in Figure 20, is a double mercury switch generally designated 246 wherein the contacts 241 at one end thereof are broken before the contacts 249 at the other end are made. Switch 245 is mounted upon a support 249 that is pivotally mounted at one end upon tie-rod I95. Swiveled on the same tie-rod in association with support 249 is a hub 259 formed with an arm I having a cam roller 252 in its free end bearing upon the margin of the cam 2&6. Said hub 250 also is formed with an arm 253 extending forwardly beneath support 249, and with a rearwardly extending counterweight 254. A dog 255 is mounted upon rock-shaft H28 in position toengage the free forward end of support 249. The major portion of the cam surface of cam 2H is such as to tilt hub 256 to the angular position shown in broken lines in Figure 20, the support 249 resting by gravity upon arm 253 whereby switch contacts 24B of switch 246 are closed and switch con tacts 241 are open.

The cam 219 includes a depressed portion 2I6a adapted to cause the switch 245 to tilt to the alternative position shown in full lines in the drawings. The cam 286 is so angularly positioned with relation to cam 2 I I that switch 246 is moved to said full line position immediately after switches 222, 223 in the circuit of motor 65 are closed, and is tilted to the opposite position immediately after switches 222, 223 are opened. The construction permits switch 246 to be tilted to full line position by dog 255 at any time, and

when the motor 295 stops after solenoid M4 is de-energized, cam 2H3 will stop in the position shown in Figure 20.

The apparatus comprises other electrical devices mounted in cabinet Hi2, said devices being of standard construction so as not to require detail illustration, but which are shown diagrammatically in the wiring diagram, Figure 23, to which attention now is directed.

Power is supplied to the apparatus from; a 3- phase, 110-volt, A. C. power line 252. Associated therewith is a 3-pole master switch 25I by means of which three conductors 252, 253 and 254 respectively are connected with said power line. The three conductors mentioned furnish power for four circuits, namely, the timer circuit, the circuit for adjusting motor 65, the integrator circuit, and the stock-gauging circuit.

In the stock-gauging circuit is a step-up transformer 256 having connection on one side, through conductor 251, with power lead 252, and having connection on the other side, through conductors 258, 259 and 259 with power lead 254. Connected with transformer 256 is lamp I I4, and switch 242 in power lead 252 controls the electrical current to said transformer. Said switch 242 also controls shutter-motor I32, the latter being connected to power lead 252 through conductor 26I and to conductor 259 through conductor 262.

A full wave rectifier 264 is connected by conductor 265 to power line 252 and by conductor 266 to power conductor 262. Said rectifier transforms the A. C. power current to direct current for the electric eyes 836, Ia and grid glow tubes I46, 3

MM to which it is connected by conductor 261. Another lead 268 from rectifier 254 extends to two relay coils 216, 215a respectively, the other side of relay 219 being connected by conductor 21! to grid glow tube I46 and the other side of relay 216a being connected by conductor 212 to grid glow tube I 4611., The arrangement is such that relay 219 is operated by grid glow tube I46 when the work 21 is underweight, and relay 216a is operated by grid glow tube I49a when the work is overweight. Lamps 213, 213a may be associated with relays 210, 216a respectively for giving visible indication as to the condition of the work at all times. The switch 242 also controls power to the rectifier 264.

The integrator circuit comprises a potentiometer 215 connected by conductor 216 with power lead 252 and connected by conductor 211 with power conductor 259. A transformer 218 is connected to conductor 211, and a transformer 219 is connected to conductor 216. Field coils I5I of the disc motor are connected with transformer 218, and field coils I5Ia are connected with transformer 219. Said field coils are connected toeach other by conductor 289 which in turn is connected by conductor 28I with one contact of each pair of switch contacts 241, 248 of mercury switch 246. Potential coil 553 of the disc motor is connected to transformer 218 and to conductor 28I and potential coil I53a is connected to transformer 219 and to conductor 28I. Associated with relay 210 is a pair of normally open contacts that are closed by operation of said relay, one of said contacts being connected by conductor 283 to a tap off potentiometer 215 and the other contact being connected by conducto to the other of switch contacts 248 of sw' Relay 210a is provided with a si contacts, one of which is connect 285 to another tap off pote the other is connected by conductor 286 to conductor 234. A third tap from the potentiometer is connected through conductor 28'! to brush I10 of the disc motor. A fourth tap from the potentiometer is connected through conductor 268 to brush I750. of the disc motor. A conductor I'I'I extends from the other of switch contacts 241 to contact plate I63 of the integrator and, through resistance coil I65, to the plate sections I64 thereof.

The arrangement is such that during normal operation of the apparatus, while switch contacts 248 are closed, underweight and/or overweight conditions of the strip 2'? alternatively periodically operate relays 2110, 210a whereby coils I5I, I5Ia, I53, I53a are energized to drive the disc motor in counterclockwise or clockwise direction respectively, accordingly as current from the potentiometer flows to the coils over conductor 283 or 285. Thus the angular position of contact plate IE3 at any time during the interval switch 293 is closed represents the mean condition of the strip 21 since the previous conveyor speed adjusting operation. If the mean condition of the strip 2? is underweight, the contact plate I63 will have moved in counter clockwise direction from neutral position and will be in contact with brush H0. If it has moved in clockwise direction it will be in contact with brush flea. In either case the switches I90 on the integrator will be closed. When the timing mechanism operates to tilt switch 240 to open contacts 298 and close contacts 29'! thereof, current from the potentiometer flows to the disc motor coils over conductors 28'! or 288 and is approximately 90 out of phase from the current previously flowing to said coils, so that the motor disc and contact plate I 63 move back to neutral position, the interval required to effect this depending upon the angular distance from neutral that the contact plate previously has been moved by the work-gauging mechanism, in no event exceeding 5.6 seconds.

When the contact plate I63 reaches neutral position it is out of contact with either brush I70 or I'IIla, so that further angular movement of the disc motor is prevented and as it comes to rest the switches I90 tilt to neutral position. This may happen of course before the timing device again tilts switch 246, and it serves to stop the drive of adjusting motor 65. The circuit for adjusting motor 65 comprises power lead 29I connected to power lead 252, and power lead 253, switches 222 and 223 being mounted in leads I, 253 respectively. The leads 29I, 253 are connected to the middle poles of the respective switches I90. From switches I90 a pair of conductor wires 292 extend to one of the end poles of a pair of 3-pc1e mercury switches 293, 293 that are mounted to be rocked by a relay 294 across conductors 292. From the middle poles of switches 293 a pair of conductor wires 295 extend to motor 55, the other conductor to said motor being power lead 254. From the other end poles of switches 293, a pair of conductors 296 extend to a rectifier 291 connected to power leads 253, 29! by conductors 293. The arrangement is such that when switches 222 and 223 are closed and switches I90 are tilted either way from neutral position, relay 294 is energized and alternating current flows to motor 65 to drive the same. When switches 222, 223 open or when switches I90 move to neutral position to open the circuit, relay 294 is de-energized and switches 293 tilt to the position shown whereby direct current from rectifier 291 flows to motor 65 and acts as a magnetic brake to stop rotation thereof. It will be seen that switches I90 constitute a reversing switch and that motor 05 is driven in one direcion or the other as the switches I90 are tilted one way or the other from neutral position.

For driving the motor 206 of the timing device, one side thereof is connected by conductor 390 to power lead 252 and its other side is connected by conductor 30I to power lead 259. Switches 229 and 233 are mounted in series in conductor 530i so as to stop rotation of motor 205 when solenoid 2I4 is de-energized as previously explained. Power is supplied to solenoid coil 2M through a pair of conductors 302, 302, one of which is connected to conductor 300 and the other to power lead 259. In one of said conductors 302 is mounted a pair of series-connected, manually operated switches 303, 304. These switches preferably are mounted adjacent opposite ends of the apparatus so that an operator may conveniently start or stop the operation of the adjusting apparatus at will. Switches 93 and 503 also are mounted in this same conductor 302 so as automatically to de-energize the solenoid 2% as previously explained.

The drawings (Figures 1 and 2) show the apparatus as it appears with motor 26 running, extruding machine forming a continuous strip of plastic material 21, and motor 51 running so that conveyor belts 29, and 40 are driven to feed the strip 21 longitudinally. Thus switch I03 and centrifugal switch 93 are closed as shown in Figure 6. The various instrumentalities of the conveyor-speed-adjusting mechanism are shown in the inoperative position they assume when master switch 25I is open, or when either of switches 393, 394 is open. The wiring diagram, Figure 23, shows the electrical apparatus in this condition.

Operation In the operation of the apparatus, assuming it to be in the condition shown, master switch 25! is closed and either switch 303, 304 closed. The first effect is to energize solenoid 2M and thereby to close switch 292 which controls the light-sensitive-gauging mechanism and disc motor, to withdraw pawl 238 from ratchet 2I2, and to close switch 229 so that motor 206 is driven to rotate cam-shaft I9! of the timing device. Immediately the cam-shaft starts rotating, cam 2I0 tilts switch 246 so that switch contacts 248 are closed and switch contacts 291 are opened. Closing of switch 242 causes lamp M4 to be lighted, and motor I32 to be driven to rotate shutter I25 with the result that as arm I08 is moved from vertical position by offgauge condition of strip 21, a beam of light is periodically projected upon one or the other of the light-sensitive members I39 or I39a. This happens every two and one-half seconds, and the length of time that the beam remains on the light-sensitive device is in direct proportion to the extent that the strip is oil gauge. The lightsensitive devices control the operation of relays 2'l0, 210a, and through the latter control the direction and duration of rotation of the disc motor and contact plate I63 of the integrating device. The integrating device controls the position of switches I90, tilting them one way or the other according to the off-gauge condition of the work.

After the operations dscribed have continued for about 28 seconds, cam 2II tilts switches 222 

